include/ptclib/podbc.h

/*
 * podbc.h
 *
 * Virteos ODBC Implementation for PWLib Library.
 *
 * Virteos is a Trade Mark of ISVO (Asia) Pte Ltd.
 *
 * Copyright (c) 2005 ISVO (Asia) Pte Ltd. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 *
 * The Original Code is derived from and used in conjunction with the
 * pwlib Libaray of the OpenH323 Project (www.openh323.org/)
 *
 * The Initial Developer of the Original Code is ISVO (Asia) Pte Ltd.
 *
 *   Portions: Simple ODBC Wrapper Article www.codeproject.com
 *
 * Contributor(s): ______________________________________.
 *
 * $Revision: 24177 $
 * $Author: rjongbloed $
 * $Date: 2010-04-05 06:52:04 -0500 (Mon, 05 Apr 2010) $
 */

/**
  ODBC Support for PWLIB

  Class Description
   PODBC        :  Main DataBase Connection Class (Derive Class for Error Handling)
   PODBC::ConnectData :  Class used to store information for Connecting to DataSource
   PODBC::Table    :  Retrieved Data Structure (RecordSet) from Table or Select SQL Query
   PODBC::Row      :  Record Pointer Class for the PODBC::Table (PArray of Fields)
   PODBC::Field    :  Database Field Information (Field Structure & Data(Bound))
   PODBC::Field:Bind  :  DataTypes Bound to the RecordSet (change with Record Navigation)
   PDSNConnection    :  Derived Class of PODBC for ODBC Configured Connections
   PODBCStmt      :  Wrapper for RecordSet (Internal)
   PODBCRecord    :  Handle Retrieve/Post/Bind Data from RecordSet (Internal)

  Example of Use

<pre><code>
  PODBC link;
  PODBC::ConnectData data;
  data.DBPath = "test.mdb";

  if (link.DataSource(PODBC::MSAccess,data)) {
    // Load a Database Table (could also be a SELECT Query)
      PODBC::Table table(&link,"FooTable");
  // Bind to Column 1
      PODBC::Field & field = table.Column(1):
    // Display Contents
      cout << " Value " << field.AsString(); << endl;
  // Move to Record 2 of fooTable
      table[2];
  // Display contents of Record 2 Column 1
      cout << " Value " << field.AsString(); << endl;
  // Set New Value for Record 2 Field 1 of FooTable
      field.SetValue("NewValue");
  // Send Update to Database.
      field.Post();

    // To Add New Record.(with Default Values)
      table.NewRow();
  // Alter the Value of field 1
      field.SetValue("Somethng");
  // Post the New Field to the Database
      field.Post();

    // Run General Query;
      PString SQLStmt = "INSERT foo into [FooTable] ..."
    Link.Query(SQLStmt);
  }
// Disconnect from ODBC Source
  link.Disconnect();

</code></pre>
*/
//--

#ifndef PTLIB_PODBC_H
#define PTLIB_PODBC_H

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000


#if defined(P_ODBC) && !defined(_WIN32_WCE)

#include <odbcinst.h>
#include <sql.h>
#include <sqlext.h>

#ifdef _MSC_VER
 #include <tchar.h>
 #pragma comment(lib,"odbc32.lib")
 #pragma comment(lib,"odbcCP32.lib")
#else

  #ifdef UNICODE
  typedef WCHAR                 TCHAR;
  typedef LPWSTR                LPTSTR;
  typedef LPCWSTR               LPCTSTR;
  // Needs a definition one day ... #define _T(x)
  #else
  typedef CHAR                  TCHAR;
  typedef LPSTR                 LPTSTR;
  typedef LPCSTR                LPCTSTR;
  #define _T(x) x
  #endif

#endif // _MSC_VER

// Max SQL String Data Length
#define MAX_DATA_LEN 1024

/** PODBC Statement Class
  This class is use to parse store queries and Fetch data
  It is not designed to process the actual data only access it.
  PODBC::Record is used to Bind/Retrieve/Store Data Elements. .
*/


class PODBC;
class PODBCRecord;


class PODBCStmt : public PObject
{
    PCLASSINFO(PODBCStmt, PObject);

  public:
    /**@name Constructor/Deconstructor */
    //@{
    /** Constructor PODBC (Datasources call) or thro' DSNConnection (Connection call).
    In General this class is constructed within the PODBC::Table Class.
    */
    PODBCStmt(PODBC * odbc);

    /** Deconstructor. This Class should be available for the duration of which
    a specific query/table is required and be deconstructed at the time of
    the PODBC::Table deconstruction.
    */
    ~PODBCStmt();
    //@}

    /**@name Handles */
    //@{
    /** Statement Handle Created by the Query Function.
    */
    operator HSTMT() { return m_hStmt; };
    //@}


    /**@name Data Management */
    //@{
    /** IsValid Checks to ensure a Handle has been allocated and
    is effective.
    */
    PBoolean IsValid();

    /** GetChangedRowCount retreives the number of rows updated/altered by
    UPDATE/INSERT statements.
    */
    DWORD GetChangedRowCount(void);

    /** Query function is the Main function to pass SQL statements to retreive/
    add/Modify database data. It accepts generally acceptable SQL Statements.
    ie. Select * from [table-x]
    */
    PBoolean Query(PString strSQL);
    //@}

    /**@name Data Retrieval */
    //@{
    /** Fetch General call to retreive the next row of data.
    */
    PBoolean Fetch();

    /** FetchRow More detailed fetching of Rows. This allows you to fetch an
    Absolute row or a row relative to the current row fetched.
    */
    PBoolean FetchRow(PINDEX nRow,PBoolean Absolute=1);

    /** FetchPrevious Fetch the previous Row from current row.
    */
    PBoolean FetchPrevious();

    /** FetchNext: Fetch the Next row.
    */
    PBoolean FetchNext();

    /** FetchFirst Fetch the First row in the RecordSet
    */
    PBoolean FetchFirst();

    /** FetchLast Fetch the Last row in the RecordSet
    */
    PBoolean FetchLast();

    /** Cancel the Current Statement
    */
    PBoolean Cancel();
    //@}

    /**@name Utilities */
    //@{
    /** Retreive the List of Tables from the current Datasource
    The option field can be used to specify the Table Types
    ie "TABLE" for Tables or "VIEW" for preconfigured datasource
    queries. *Further investigation is required*
    */
    PStringArray TableList(PString option = "");


    /** Is the SQL Instruction OK
    If an Error is detected then GetLastError is called
    to Retrieve the SQL Error Information and Returns false
    */
    PBoolean SQL_OK(SQLRETURN res);

    /** Get the Last Error
    This returns the Error ID & String to PODBC::OnSQLError
    */
    void GetLastError();

    PODBC * GetLink() const { return odbclink; }
    int GetDBase() const { return dbase; }
    //@}

  protected:
    HSTMT   m_hStmt;
    PODBC * odbclink; /// Reference to the PODBC Class
    int     dbase;    /// Database Type connecting to
};


/** PODBC Class
  The Main ODBC class. This Class should be used in the there is
  not a preconfigured DSN setup in the MDAC. This class will use
  the applicable ODBC drivers to connect to a compliant Datasource.
  It Supports a wide variety of Datasources but others can added
  by simply creating your custom connection string and then calling
  PODBC::Connect. For Defined sources the PODBC::DataSource function
  should be used.
*/

class PODBC  : public PObject
{
    PCLASSINFO(PODBC, PObject);

  public:
    /**@name Constructor/Deconstructor */
    //@{
    /** Constructor
    */
    PODBC();

    /** Deconstructor
    */
    ~PODBC();
    //@}

    /**@name Enumerators */
    //@{
    /** Raw SQL data type codes Refer <sql.h> SQL_*
    This list is not inclusive. If an item
    is not listed or Unknown it is treated
    as a character string.

    */
    enum FieldTypes
    {
      LongVarChar   =-1,
      Binary        =-2,
      VarBinary     =-3,
      LongVarBinary =-4,
      BigInt        =-5,
      TinyInt       =-6,
      Bit           =-7,   /// Boolean
      Guid          =-11,
      Unknown       = 0,
      Char          = 1,
      Numeric       = 2,
      Decimal       = 3,
      Integer       = 4,
      SmallInt      = 5,
      Float         = 6,
      Real          = 7,
      Double        = 8,
      DateTime      = 9,
      VarChar       =12,
      Date          =91,    /// Structure
      Time          =92,    /// Structure
      TimeStamp     =93     /// Structure  PTime
    };

    /** Converted Pwlib Field Types.
    Data is stored as a PString
    and the pwType enumerator indicates
    the conversion required on the PODBC::Field.
    */
    enum PwType
    {
      oPString,   // String Value
      oBOOL,      // Boolean
      ochar,      // Character
      oshort,     // Short
      oint,       // Integer  use .AsInteger()
      olong,      // long
      odouble,    // Double   use .AsReal()
      oPBYTEArray,// Binary Data
      oPInt64,    // BigInt  use .AsInt64()
      oPTime,     // Time    use  PTime( "Value" )
      oPGUID      // GUID    use  PGUID( "Value" ) To Be Implemented...?
    };

    /** Datasources that are supported by this implementation
    used in the PODBC::DataSource Function.
    */

    enum DataSources
    {
      mySQL,
      MSSQL,
      Oracle,
      IBM_DB2,
      DBASE,
      Paradox,
      Excel,
      Ascii,
      Foxpro,
      MSAccess,
      postgreSQL
    };

    /** MSSQL protocols.If your interested?
    */
    enum MSSQLProtocols
    {
      MSSQLNamedPipes,
      MSSQLWinSock,
      MSSQLIPX,
      MSSQLBanyan,
      MSSQLRPC
    };

    //@}

    /**@name Connection Class */
    //@{
    /** This class is a multipurpose use
    class for storing parameters when
    initiating connection to DataSource.
    Not all field are required. By default
    all non-essential params are set to a
    datasource specific default value.
    */
    class ConnectData
    {
    public:
      PFilePath DBPath;    /// Database file Path (not Oracle,xxSQL)
      PString DefDir;     /// Used with Paradox/DBase/Excel (& mySQL db)
      PString User;       /// UserName
      PString Pass;       /// Password
      PBoolean Excl_Trust;     /// Whether Datasource is locked or Trusted.
      PString Host;       /// URL for Host Datasouce xxSQL
      int Port;         /// Port to connect to mySQL
      int opt;         /// General Option Value.mySQL & Paradox
    };
    //@}


    /**@name Database Field Class */
    //@{
    /** Class for Field Data
    */
    class Row;
    class Field : public PObject
    {
        PCLASSINFO(Field, PObject);
      public:

        /** SQL compliant Bound DataTypes.
        The appropriate Field is bound
        to the SQL Driver and alters
        when a new record is fetched.
        */
        class Bind
        {
          public:
            PString          sbin;      /// Strings & Binary Data
            PString          sbinlong;  /// Long Data
            short int        ssint;     /// Short Integer    SQLSMALLINT
            long int         slint;     /// Integer        SQLINTEGER
            double           sdoub;     /// Double        SQLDOUBLE
            unsigned char    sbit;      /// Bit          SQLCHAR
            unsigned char *  suchar;    /// Unsigned char    SQLCHAR *
            PInt64           sbint;     /// Bit Integer      SQLBIGINT
            DATE_STRUCT      date;      /// Date Structure
            TIME_STRUCT      time;      /// Time Structure
            TIMESTAMP_STRUCT timestamp; /// TimeStamp Structure
            SQLGUID          guid;      /// GUID Structure (not Fully Supported)
            SQLLEN           dataLen;   /// DataLength pointer (StrLen_or_Ind for Col Bind)
        };

        /** Post the Changes back to the Database
        */
        PBoolean Post();

        /** Returns a String representation of the field.
        */
        PString operator=(const PString & str);

        /** Display the Field Data as String
        */
        PString AsString();

        /** Set the Field Data. Note a Post() must be called
        to post the changes back to the database.
        */
        void SetValue(PString value);  /// Set the Value

        /** Initialise/Set the Default values for Field of New Record
        */
        void SetDefaultValues();

        /** DataFragment Data is broken into fragment to be passed
        to the Database
        */
        PBoolean DataFragment(PString & Buffer ,PINDEX & fragment, SQLINTEGER & size);

        /** Settings
        */
        /// Data
        Bind  Data;       /// Data Field to ODBC Bind to
        PwType  Type;       /// pwlib Type for conversion
        FieldTypes ODBCType;   /// ODBC Type (For saving/Conversion)

        /// Column
        PString Name;       /// Column Name
        PINDEX col;       /// Column Number (For Saving/Conversion)

        /// Column Attributes
        PBoolean isReadOnly;     /// Is Field Readonly
        PBoolean isNullable;     /// Allows Nulls
        PBoolean isAutoInc;     /// Field AutoIncrements
        int Decimals;       /// Number of decimal places to Round
        PBoolean LongData;     /// LongData Length is Required

        /// RecordHolder Reference
        Row * row;       /// Back Reference to the Row
    };
    //@}


    /**@name Database Row Class */
    //@{
    /** This class functions as a simple wrapper
    of the PODBCStmt class to fetch/Save
    data to the Datasource. Data is fetched
    on a need to basis and not cached except
    to create a new row.
    */
    class Row : public PObject
    {
      public:

        /** Constructor
        Create a Dummy row of data to act as a
        Record Marker. Template Field are created
        and Stored in a PARRAY.
        */
        Row(PODBCStmt * stmt);

        /** Retrieve Field Data given the specifed column.
        Note: Columns atart at 1 and not exceed PODBCStmt::GetColumnCount()
        */
        Field & Column(PINDEX col);

        /** Retreive Field Data given the Column Name
        */
        Field & Column(PString name);

        /** Retrieve the Column Names
        */
        PStringArray ColumnNames();

        /** Columns. The Number of Columns in the RecordSet
        */
        PINDEX Columns();

        /** Rows  The Number of Rows
        */
        PINDEX Rows();

        /** Retrieve Field Data given specified column
        */
        Field & operator[] (PINDEX col);

        /** Retrieve Field Data given the column Name.
        */
        Field & operator[] (PString col);

        /** Navigate to Specified Row
        */
        PBoolean Navigate(PINDEX row);

        /** SetNewRow Set New Row for input
        */
        void SetNewRow();

        /** Post the Row back to the Database.
        When Row::NewRow is true the data
        can be posted back to the Database;
        If Edit Invoked then releasea the
        RowHandler for Navigation.
        */
        PBoolean Post();

        /** Delete the Current Record from the
        RecordSet
        */
        PBoolean Delete(PINDEX row =0);

        PODBCRecord * rec;      /// Record Structure

        PINDEX CurRow;          /// Current Row
        PBoolean NewRow;        /// Flag to Indicate New Row (requires either Post or Delete)
        PINDEX RowCount;      /// Number of Rows.

      protected:
        PArray<Field> Fields;    /// PODBC::Field Array Cache (Used for New Row)
    };
    //@}

    /** PODBC::Table
    This is the main Class to access Data returned by a Select Query.
    The Table does not actually create the RecordSet but acts as a wrapper
    to the driver to access the cached data in the Driver.
    */
    class Table : public PObject
    {
      public:

        /**@name Constructor/Deconstructor */
        //@{
        /** Constructor
        Using the HDBC and TableName/Select SQL Query
        creates a virtual Table in the OBDC driver.
        */
        Table(PODBC * odbc, PString Query);

        /** Deconstructor
        */
        ~Table();
        //@}

        /**@name Data Storage */
        //@{
        /** Add New Row
        */
        Row NewRow();

        /** Delete Row 0 indicates Current Row
        */
        PBoolean DeleteRow(PINDEX row = 0);

        /** Post Update back to Database
        */
        PBoolean Post();
        //@}

        /**@name Utilities */
        //@{
        /** Rows. Returns the Number of Rows in the Resultant RecordSet
        */
        PINDEX Rows();

        /** Columns. Returns the Number of Columns in the Resultant RecordSet
        */
        PINDEX Columns();

        /** ColumnNames. Return the list of column Names of the Resultant RecordSet
        */
        PStringArray ColumnNames();

        /** Obtain the Record Handler. This can be used as a Template to obtain
        Record Information. A call to tablename[i] will update the recordHandler
        with the Values contained in i Record.
        */
        Row & RecordHandler();

        /** Row return the fetched row in the Cached RecordSet. An Array of PODBC::Field
        */
        Row & operator[] (PINDEX row);

        /** Returns the Field data at a predetermined position in the Resultant
        RecordSet. It Fetches the Row than isolates the Column from the fetched
        data.
        */
        Field & operator() (PINDEX row, PINDEX col);

        /** Returns the indicated Column Holder for the RecordSet,
        This can be used for iterative Row calls.
        */
        Field & Column(PINDEX col);

        /** Returns the indicated Column Holder Name for the RecordSet,
        */
        Field & Column(PString Name);
        //@}

      protected:
        PODBCStmt stmt;      /// ODBC Fetched Statement Info
        PString tableName;    /// Name of the Fetched Table (if used in Constructor)
        Row * RowHandler;      /// row Handler
    };

    /**@name Data Queries */
    //@{
    /** Load a specified Table/Stored Query or
    General 'SELECT' SQL Query.
    This function will return a PODBC::Table for
    further analysis. Do Not Use this Function for
    any other SQL statements other than SELECT.
    */
    Table LoadTable(PString table);

    /** Added Information to the DataSource. Use this
    function if you just want to use a SQL statement
    to add data to a datasource without retreiving the
    data itself. ie "UPDATE" "APPEND" "INSERT" queries.
    */
    PBoolean Query(PString Query);
    //@}


    /**@name DataSource Access */
    //@{
    /** DataSource
    This is the main function to call to contact a
    DataSource. Source specifies the Type of DataSource
    to contact and the Data parameter contain the relevent
    connection information. You can choose to call this function
    or use the specific Connection function.
    */
    PBoolean DataSource(DataSources Source, ConnectData Data);

    /** General Connect Function
    Custom connection strings should call this
    to connect Don't ask why its LPCTSTR!
    */
    virtual PBoolean Connect(LPCTSTR svSource);

    /** Connect to IBM DB2 DataSource
    */
    PBoolean Connect_DB2(PFilePath DBPath);

    /** Connect to MS Office excel spreadsheet
    */
    PBoolean Connect_XLS(PFilePath XLSPath,PString DefDir = "");

    /** Connect to an ascii text or cvs file
    */
    PBoolean Connect_TXT(PFilePath TXTPath);

    /** Connect to a Foxpro dataSource
    */
    PBoolean Connect_FOX(PFilePath DBPath,PString User = "",
      PString Pass = "",PString Type= "DBF",
      PBoolean Exclusive=false);

    /** Connect to a MS Access *.mdb DataSource.
    */
    PBoolean Connect_MDB(PFilePath MDBPath,PString User ="",
      PString Pass = "",PBoolean Exclusive=false);

    /** Connect to a paradox database datastore
    */
    PBoolean Connect_PDOX(PDirectory DBPath,PDirectory DefaultDir,
      int version =5);

    /** Connect to an Oracle Datasource
    */
    PBoolean Connect_Oracle(PString Server,PString User="", PString Pass="");

    /** Connect to a DBase DataStore
    */
    PBoolean Connect_DBASE(PDirectory DBPath);

    /** Connect to a MS SQL Server
    */
    PBoolean Connect_MSSQL(PString User="",PString Pass="",
      PString Host ="(local)",PBoolean Trusted = true,
      MSSQLProtocols Proto=MSSQLNamedPipes);

    /** Connect to a mySQL Server
    */
    PBoolean Connect_mySQL(PString User="",PString Pass="",
      PString Host= "localhost",
      int Port=3306,int Option=0);

    /** Connect to a mySQL Server's specified DataBase.
    */
    PBoolean ConnectDB_mySQL(PString DB,PString User="",
      PString Pass="",PString Host= "localhost",
      int Port=3306,int Option=0);

    /** Connect to a postgreSQL Server
    */
    PBoolean Connect_postgreSQL(PString DB,PString User,
      PString Pass,PString Host, int Port=5432,int Option=0);

    /** General Disconnect from DataSource.
    */
    void Disconnect();
    //@}

    /**@name Utilities */
    //@{
    /** Retrieve a List of Tables in the Datasource
    use the option field to specify the type of
    data to access. ie "TABLE" or "VIEW" (further dev req'd)
    */
    PStringArray TableList(PString option = "");

    /** Check whether their is a limit to Datalength
    when obtaining Long Data
    */
    PBoolean NeedLongDataLen();

    /** OnSQL Error
    */
    virtual void OnSQLError(PString RetCode, PString RetString) {};


    /** Set the Number of Decimal places to
    round to By Default it is 4. However if the field
    decimal places is less then Precision Value the
    field rounding will be used. This must be set prior
    to calling LoadTable()
    */
    void SetPrecision(int Digit);

    /** Set the Time Display Format
    */
    void SetTimeFormat(PTime::TimeFormat tformat);

    /** Operator Handle DataBase Connection
    */
    operator HDBC() { return m_hDBC; };
    //@}

    PODBC::DataSources  dbase; /// Database Type connected to

  protected:
    SQLRETURN       m_nReturn;      // Internal SQL Error code
    HENV            m_hEnv;         // Handle to environment
    HDBC            m_hDBC;         // Handle to database connection
};


/**
  DSN (Data Source Name) Connection. The connection settings
  have been preconfiured in the MDAC (Microsoft Data Access Component)
  and is called using those Preset Settings. Calling the PDSNConnection::Connect
  has the same effect and is a replaceable for PODBC::DataSource,
 */
class PDSNConnection : public PODBC
{
    PCLASSINFO(PDSNConnection, PODBC);

  public:
    /**@name Constructor/Deconstructor */
    //@{
    PDSNConnection();
    ~PDSNConnection();
    //@}

    /**@name Connection/Disconnect */
    //@{
    /** Connect to the MDAC using a pre-existing MDAC Defined DataSource
    This is different than calling PODBC::DataSource in that the
    Data Source is known defined externally within MDAC,
    */
    PBoolean Connect( PString Source ,PString Username, PString Password);
};


 //--
/** PODBCRecord
    This Class is used to analyse the fetched data and handles
    Data Conversion/Read Write operations. It is used in conjuction
    with the PODBCStmt Class
*/

class PODBCRecord : public PObject
{
    PCLASSINFO(PODBCRecord, PObject);

  public:
    /**@name Constructor/Deconstructor */
    //@{
    /** Constructor
    */
    PODBCRecord(PODBCStmt * hStmt);

    /** Deconstructor
    */
    ~PODBCRecord(){};
    //@}

    /**@name Data Collection/Saving */
    //@{
    /** Data: Main Call to retrieve and convert Field Data
    and return the information in the PODBC::Field structure.
    */
    void Data(PINDEX Column, PODBC::Field & field);

    /** InternalGetData is call when retrieving string or large binary
    data where the size is indetermined. The Function can be iteratively
    called until the function returns false.
    */
    PBoolean InternalGetData(
      USHORT Column,
      LPVOID pBuffer,
      ULONG pBufLen,
      SQLINTEGER * dataLen=NULL,
      int Type=SQL_C_DEFAULT
      );

    /* Get Long Character Data. Long Data fields cannot be bound
    and Data must be Got from the RecordSet.
    */
    PString GetLongData(PINDEX Column);

    /** Post the new record back to the RecordSet;
    */
    PBoolean PostNew(PODBC::Row & rec);

    /** Post the Updated record back to the RecordSet;
    */
    PBoolean PostUpdate(PODBC::Row & rec);

    /** Post a Delete command to the RecordSet; Default
    1 Row is deleted.
    */
    PBoolean PostDelete(PINDEX row= 1);

    /** Check for and Save Long Data
    */
    PBoolean InternalSaveLongData(SQLRETURN nRet,PODBC::Row & rec);

    /** InternalBindColumn for Data input.
    */
    PBoolean InternalBindColumn(
      USHORT Column,LPVOID pBuffer,
      ULONG pBufferSize,
      LONG * pReturnedBufferSize=NULL,
      USHORT nType=SQL_C_TCHAR
      );
    //@}

    /**@name Data Information */
    //@{
    /** ColumnByName returns the column number of the column name
    If not found returns column value of 0;
    */
    PINDEX ColumnByName(PString Column);

    /** ColumnCount No of columns
    */
    PINDEX ColumnCount();

    /** ColumnTypes
    */
    PODBC::FieldTypes ColumnType(PINDEX Column );

    /** Column Size
    */
    DWORD ColumnSize( PINDEX Column );

    /** Column Scale
    */
    DWORD ColumnScale( PINDEX Column );

    /** Column Name
    */
    PString ColumnName( PINDEX Column);

    /** ColumnPrecision Get the Number of Decimal places
    if Precision is set the precision is set to the
    lessor of the Two.
    */
    unsigned int ColumnPrecision( PINDEX Column );

    /** IsColumn Nullable. Accepts NULL value
    */
    PBoolean IsColumnNullable( PINDEX Column );

    /** IsColumn Updateable ie is not ReadOnly
    */
    PBoolean IsColumnUpdatable( PINDEX Column );

    /** IsColumnAutoIndex (ie don't give default Value)
    */
    PBoolean IsColumnAutoIndex( PINDEX Column );

    //@}

    /**@name Data Conversion Settings */
    //@{
    /** Conversion Settings
    */
    static unsigned int Precision;      /// Double Real Float Decimal digit rounding def= 4;
    static int MaxCharSize;          /// Long Data Limit KBytes def = 56; (56 Kbytes)
    static PTime::TimeFormat TimeFormat;/// Time Format
    //@}

  protected:
    HSTMT m_hStmt;
    PODBCStmt * Stmt;          /// Statement Class
    PODBC::DataSources dbase;      /// Database Type connecting to

  friend class PODBC::Field;
  friend class PODBC::Row;
};

#endif // P_ODBC

#endif // PTLIB_PODBC_H


// End Of File ///////////////////////////////////////////////////////////////